In September, the same court official cited Ms Spears' "habitual, frequent and continuous" drugs and alcohol use.

Scott Gordon has previously granted Ms Spears visitation rights only to suspend them on her failure to comply with court orders. He later restored the visits, but on condition they were attended by a court-approved monitor.

In Tuesday's ruling Ms Spears was granted two afternoons and one full night per week with her two sons.

But as conditions for the visits to take place, she was also ordered to childproof her house, work out a schedule for the visits with Mr Federline, and use car seats when driving her children around.

'Chaotic'

The judgement comes after a three-hour hearing last Friday, which both Ms Spears, 25, and Mr Federline, 29, attended.

Detailed testimony was presented, from Ms Spears' parenting coach Lisa Hacker among others. Ms Hacker's report concluded that the singer loved her sons and that they were bonded to her.

But it also criticised Ms Spears, calling the atmosphere at her home "chaotic" and saying she rarely played with or spoke to the boys.

"It seems that her choices are dependent more upon what she wants to do at any given time rather than what would be more enjoyable for the children," Ms Hacker said in her assessment.

A full evaluation of the custody arrangements is not expected to be completed until mid-January, according to news agency Reuters.